As mentioned it's not always as easy as buy a proven pair, get fry in a month-- sometimes yes, sometimes no. But depending where you are and the quality of shops in your area it may be possible to hand pick nice adults or near adults and see if you can get a pair. Same thing if there are decent breeders in your area or a cichlid association where members buy and sell-- you never know what you can pick up from someone who wants to move on to something else.
I say this because I've done it-- both ways. First time was years ago, bought the fish because I liked the fish-- I lived in a place at the time with some really good shops, way beyond the typical PetSmart or non-descript little pet stores. Then it's a matter of waiting for nature to take its course-- or not. I didn't have any secret formula besides picking nice fish and keeping a healthy tank. I kept them with compatible SAs, it wasn't just a breeding tank, especially aesthetically. Imo tank size helps also, not a cosmic law but it helps for your fish to feel comfortable in their surroundings.
Pair forming can appear to be hit or miss or it can simply take time and patience. Assuming a tank and water conditions they like are already a given, food can make a difference ime, years ago I fed a lot of live brine shrimp, last time-- wild Peru angelfish-- freeze dried blood worms seemed to make them happy. I was never set on breeding them, for me it was more about the type of tank I was doing, but in doing that breeding happened. Interesting what happens sometimes when you're not in a hurry.
...my opinions, based on personal experience